/*
* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
/**
* @file
*
* Linux bzImage image format
*
*/
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <realmode.h>
#include <bzimage.h>
#include <gpxe/uaccess.h>
#include <gpxe/image.h>
#include <gpxe/segment.h>
#include <gpxe/init.h>
#include <gpxe/cpio.h>
#include <gpxe/features.h>
FEATURE ( FEATURE_IMAGE, "bzImage", DHCP_EB_FEATURE_BZIMAGE, 1 );
struct image_type bzimage_image_type __image_type ( PROBE_NORMAL );
/**
* bzImage context
*/
struct bzimage_context {
/** Boot protocol version */
unsigned int version;
/** Real-mode kernel portion load segment address */
unsigned int rm_kernel_seg;
/** Real-mode kernel portion load address */
userptr_t rm_kernel;
/** Real-mode kernel portion file size */
size_t rm_filesz;
/** Real-mode heap top (offset from rm_kernel) */
size_t rm_heap;
/** Command line (offset from rm_kernel) */
size_t rm_cmdline;
/** Command line maximum length */
size_t cmdline_size;
/** Real-mode kernel portion total memory size */
size_t rm_memsz;
/** Non-real-mode kernel portion load address */
userptr_t pm_kernel;
/** Non-real-mode kernel portion file and memory size */
size_t pm_sz;
/** Video mode */
unsigned int vid_mode;
/** Memory limit */
uint64_t mem_limit;
/** Initrd address */
physaddr_t ramdisk_image;
/** Initrd size */
physaddr_t ramdisk_size;
/** Command line magic block */
struct bzimage_cmdline cmdline_magic;
/** bzImage header */
struct bzimage_header bzhdr;
};
/**
* Parse bzImage header
*
* @v image bzImage file
* @v bzimg bzImage context
* @v src bzImage to parse
* @ret rc Return status code
*/
static int bzimage_parse_header ( struct image *image,
struct bzimage_context *bzimg,
userptr_t src ) {
unsigned int syssize;
int is_bzimage;
/* Sanity check */
if ( image->len < ( BZI_HDR_OFFSET + sizeof ( bzimg->bzhdr ) ) ) {
DBGC ( image, "bzImage %p too short for kernel header\n",
image );
return -ENOEXEC;
}
/* Read in header structures */
memset ( bzimg, 0, sizeof ( *bzimg ) );
copy_from_user ( &bzimg->cmdline_magic, src, BZI_CMDLINE_OFFSET,
sizeof ( bzimg->cmdline_magic ) );
copy_from_user ( &bzimg->bzhdr, src, BZI_HDR_OFFSET,
sizeof ( bzimg->bzhdr ) );
/* Calculate size of real-mode portion */
bzimg->rm_filesz =
( ( bzimg->bzhdr.setup_sects ? bzimg->bzhdr.setup_sects : 4 ) + 1 ) << 9;
if ( bzimg->rm_filesz > image->len ) {
DBGC ( image, "bzImage %p too short for %zd byte of setup\n",
image, bzimg->rm_filesz );
return -ENOEXEC;
}
bzimg->rm_memsz = BZI_ASSUMED_RM_SIZE;
/* Calculate size of protected-mode portion */
bzimg->pm_sz = ( image->len - bzimg->rm_filesz );
syssize = ( ( bzimg->pm_sz + 15 ) / 16 );
/* Check for signatures and determine version */
if ( bzimg->bzhdr.boot_flag != BZI_BOOT_FLAG ) {
DBGC ( image, "bzImage %p missing 55AA signature\n", image );
return -ENOEXEC;
}
if ( bzimg->bzhdr.header == BZI_SIGNATURE ) {
/* 2.00+ */
bzimg->version = bzimg->bzhdr.version;
} else {
/* Pre-2.00. Check that the syssize field is correct,
* as a guard against accepting arbitrary binary data,
* since the 55AA check is pretty lax. Note that the
* syssize field is unreliable for protocols between
* 2.00 and 2.03 inclusive, so we should not always
* check this field.
*/
bzimg->version = 0x0100;
if ( bzimg->bzhdr.syssize != syssize ) {
DBGC ( image, "bzImage %p bad syssize %x (expected "
"%x)\n", image, bzimg->bzhdr.syssize, syssize );
return -ENOEXEC;
}
}
/* Determine image type */
is_bzimage = ( ( bzimg->version >= 0x0200 ) ?
( bzimg->bzhdr.loadflags & BZI_LOAD_HIGH ) : 0 );
/* Calculate load address of real-mode portion */
bzimg->rm_kernel_seg = ( is_bzimage ? 0x1000 : 0x9000 );
bzimg->rm_kernel = real_to_user ( bzimg->rm_kernel_seg, 0 );
/* Allow space for the stack and heap */
bzimg->rm_memsz += BZI_STACK_SIZE;
bzimg->rm_heap = bzimg->rm_memsz;
/* Allow space for the command line */
bzimg->rm_cmdline = bzimg->rm_memsz;
bzimg->rm_memsz += BZI_CMDLINE_SIZE;
/* Calculate load address of protected-mode portion */
bzimg->pm_kernel = phys_to_user ( is_bzimage ? BZI_LOAD_HIGH_ADDR
: BZI_LOAD_LOW_ADDR );
/* Extract video mode */
bzimg->vid_mode = bzimg->bzhdr.vid_mode;
/* Extract memory limit */
bzimg->mem_limit = ( ( bzimg->version >= 0x0203 ) ?
bzimg->bzhdr.initrd_addr_max : BZI_INITRD_MAX );
/* Extract command line size */
bzimg->cmdline_size = ( ( bzimg->version >= 0x0206 ) ?
bzimg->bzhdr.cmdline_size : BZI_CMDLINE_SIZE );
DBGC ( image, "bzImage %p version %04x RM %#lx+%#zx PM %#lx+%#zx "
"cmdlen %zd\n", image, bzimg->version,
user_to_phys ( bzimg->rm_kernel, 0 ), bzimg->rm_filesz,
user_to_phys ( bzimg->pm_kernel, 0 ), bzimg->pm_sz,
bzimg->cmdline_size );
return 0;
}
/**
* Update bzImage header in loaded kernel
*
* @v image bzImage file
* @v bzimg bzImage context
* @v dst bzImage to update
*/
static void bzimage_update_header ( struct image *image,
struct bzimage_context *bzimg,
userptr_t dst ) {
/* Set loader type */
if ( bzimg->version >= 0x0200 )
bzimg->bzhdr.type_of_loader = BZI_LOADER_TYPE_GPXE;
/* Set heap end pointer */
if ( bzimg->version >= 0x0201 ) {
bzimg->bzhdr.heap_end_ptr = ( bzimg->rm_heap - 0x200 );
bzimg->bzhdr.loadflags |= BZI_CAN_USE_HEAP;
}
/* Set command line */
if ( bzimg->version >= 0x0202 ) {
bzimg->bzhdr.cmd_line_ptr = user_to_phys ( bzimg->rm_kernel,
bzimg->rm_cmdline );
} else {
bzimg->cmdline_magic.magic = BZI_CMDLINE_MAGIC;
bzimg->cmdline_magic.offset = bzimg->rm_cmdline;
bzimg->bzhdr.setup_move_size = bzimg->rm_memsz;
}
/* Set video mode */
bzimg->bzhdr.vid_mode = bzimg->vid_mode;
/* Set initrd address */
if ( bzimg->version >= 0x0200 ) {
bzimg->bzhdr.ramdisk_image = bzimg->ramdisk_image;
bzimg->bzhdr.ramdisk_size = bzimg->ramdisk_size;
}
/* Write out header structures */
copy_to_user ( dst, BZI_CMDLINE_OFFSET, &bzimg->cmdline_magic,
sizeof ( bzimg->cmdline_magic ) );
copy_to_user ( dst, BZI_HDR_OFFSET, &bzimg->bzhdr,
sizeof ( bzimg->bzhdr ) );
DBGC ( image, "bzImage %p vidmode %d\n", image, bzimg->vid_mode );
}
/**
* Parse kernel command line for bootloader parameters
*
* @v image bzImage file
* @v bzimg bzImage context
* @v cmdline Kernel command line
* @ret rc Return status code
*/
static int bzimage_parse_cmdline ( struct image *image,
struct bzimage_context *bzimg,
const char *cmdline ) {
char *vga;
char *mem;
/* Look for "vga=" */
if ( ( vga = strstr ( cmdline, "vga=" ) ) ) {
vga += 4;
if ( strcmp ( vga, "normal" ) == 0 ) {
bzimg->vid_mode = BZI_VID_MODE_NORMAL;
} else if ( strcmp ( vga, "ext" ) == 0 ) {
bzimg->vid_mode = BZI_VID_MODE_EXT;
} else if ( strcmp ( vga, "ask" ) == 0 ) {
bzimg->vid_mode = BZI_VID_MODE_ASK;
} else {
bzimg->vid_mode = strtoul ( vga, &vga, 0 );
if ( *vga && ( *vga != ' ' ) ) {
DBGC ( image, "bzImage %p strange \"vga=\""
"terminator '%c'\n", image, *vga );
}
}
}
/* Look for "mem=" */
if ( ( mem = strstr ( cmdline, "mem=" ) ) ) {
mem += 4;
bzimg->mem_limit = strtoul ( mem, &mem, 0 );
switch ( *mem ) {
case 'G':
case 'g':
bzimg->mem_limit <<= 10;
case 'M':
case 'm':
bzimg->mem_limit <<= 10;
case 'K':
case 'k':
bzimg->mem_limit <<= 10;
break;
case '\0':
case ' ':
break;
default:
DBGC ( image, "bzImage %p strange \"mem=\" "
"terminator '%c'\n", image, *mem );
break;
}
bzimg->mem_limit -= 1;
}
return 0;
}
/**
* Set command line
*
* @v image bzImage image
* @v bzimg bzImage context
* @v cmdline Kernel command line
* @ret rc Return status code
*/
static int bzimage_set_cmdline ( struct image *image,
struct bzimage_context *bzimg,
const char *cmdline ) {
size_t cmdline_len;
/* Copy command line down to real-mode portion */
cmdline_len = ( strlen ( cmdline ) + 1 );
if ( cmdline_len > bzimg->cmdline_size )
cmdline_len = bzimg->cmdline_size;
copy_to_user ( bzimg->rm_kernel, bzimg->rm_cmdline,
cmdline, cmdline_len );
DBGC ( image, "bzImage %p command line \"%s\"\n", image, cmdline );
return 0;
}
/**
* Load initrd
*
* @v image bzImage image
* @v initrd initrd image
* @v address Address at which to load, or UNULL
* @ret len Length of loaded image, rounded up to 4 bytes
*/
static size_t bzimage_load_initrd ( struct image *image,
struct image *initrd,
userptr_t address ) {
char *filename = initrd->cmdline;
struct cpio_header cpio;
size_t offset = 0;
/* Do not include kernel image itself as an initrd */
if ( initrd == image )
return 0;
/* Create cpio header before non-prebuilt images */
if ( filename && filename[0] ) {
size_t name_len = ( strlen ( filename ) + 1 );
DBGC ( image, "bzImage %p inserting initrd %p as %s\n",
image, initrd, filename );
memset ( &cpio, '0', sizeof ( cpio ) );
memcpy ( cpio.c_magic, CPIO_MAGIC, sizeof ( cpio.c_magic ) );
cpio_set_field ( cpio.c_mode, 0100644 );
cpio_set_field ( cpio.c_nlink, 1 );
cpio_set_field ( cpio.c_filesize, initrd->len );
cpio_set_field ( cpio.c_namesize, name_len );
if ( address ) {
copy_to_user ( address, offset, &cpio,
sizeof ( cpio ) );
}
offset += sizeof ( cpio );
if ( address ) {
copy_to_user ( address, offset, filename,
name_len );
}
offset += name_len;
offset = ( ( offset + 0x03 ) & ~0x03 );
}
/* Copy in initrd image body */
if ( address )
memcpy_user ( address, offset, initrd->data, 0, initrd->len );
offset += initrd->len;
if ( address ) {
DBGC ( image, "bzImage %p has initrd %p at [%lx,%lx)\n",
image, initrd, user_to_phys ( address, 0 ),
user_to_phys ( address, offset ) );
}
/* Round up to 4-byte boundary */
offset = ( ( offset + 0x03 ) & ~0x03 );
return offset;
}
/**
* Load initrds, if any
*
* @v image bzImage image
* @v bzimg bzImage context
* @ret rc Return status code
*/
static int bzimage_load_initrds ( struct image *image,
struct bzimage_context *bzimg ) {
struct image *initrd;
size_t total_len = 0;
physaddr_t address;
int rc;
/* Add up length of all initrd images */
for_each_image ( initrd )
total_len += bzimage_load_initrd ( image, initrd, UNULL );
/* Give up if no initrd images found */
if ( ! total_len )
return 0;
/* Find a suitable start address. Try 1MB boundaries,
* starting from the downloaded kernel image itself and
* working downwards until we hit an available region.
*/
for ( address = ( user_to_phys ( image->data, 0 ) & ~0xfffff ) ; ;
address -= 0x100000 ) {
/* Check that we're not going to overwrite the
* kernel itself. This check isn't totally
* accurate, but errs on the side of caution.
*/
if ( address <= ( BZI_LOAD_HIGH_ADDR + image->len ) ) {
DBGC ( image, "bzImage %p could not find a location "
"for initrd\n", image );
return -ENOBUFS;
}
/* Check that we are within the kernel's range */
if ( ( address + total_len - 1 ) > bzimg->mem_limit )
continue;
/* Prepare and verify segment */
if ( ( rc = prep_segment ( phys_to_user ( address ), 0,
total_len ) ) != 0 )
continue;
/* Use this address */
break;
}
/* Record initrd location */
bzimg->ramdisk_image = address;
bzimg->ramdisk_size = total_len;
/* Construct initrd */
DBGC ( image, "bzImage %p constructing initrd at [%lx,%lx)\n",
image, address, ( address + total_len ) );
for_each_image ( initrd ) {
address += bzimage_load_initrd ( image, initrd,
phys_to_user ( address ) );
}
return 0;
}
/**
* Execute bzImage image
*
* @v image bzImage image
* @ret rc Return status code
*/
static int bzimage_exec ( struct image *image ) {
struct bzimage_context bzimg;
const char *cmdline = ( image->cmdline ? image->cmdline : "" );
int rc;
/* Read and parse header from loaded kernel */
if ( ( rc = bzimage_parse_header ( image, &bzimg,
image->priv.user ) ) != 0 )
return rc;
assert ( bzimg.rm_kernel == image->priv.user );
/* Parse command line for bootloader parameters */
if ( ( rc = bzimage_parse_cmdline ( image, &bzimg, cmdline ) ) != 0)
return rc;
/* Store command line */
if ( ( rc = bzimage_set_cmdline ( image, &bzimg, cmdline ) ) != 0 )
return rc;
/* Load any initrds */
if ( ( rc = bzimage_load_initrds ( image, &bzimg ) ) != 0 )
return rc;
/* Update kernel header */
bzimage_update_header ( image, &bzimg, bzimg.rm_kernel );
/* Prepare for exiting */
shutdown ( SHUTDOWN_BOOT );
DBGC ( image, "bzImage %p jumping to RM kernel at %04x:0000 "
"(stack %04x:%04zx)\n", image, ( bzimg.rm_kernel_seg + 0x20 ),
bzimg.rm_kernel_seg, bzimg.rm_heap );
/* Jump to the kernel */
__asm__ __volatile__ ( REAL_CODE ( "movw %w0, %%ds\n\t"
"movw %w0, %%es\n\t"
"movw %w0, %%fs\n\t"
"movw %w0, %%gs\n\t"
"movw %w0, %%ss\n\t"
"movw %w1, %%sp\n\t"
"pushw %w2\n\t"
"pushw $0\n\t"
"lret\n\t" )
: : "r" ( bzimg.rm_kernel_seg ),
"r" ( bzimg.rm_heap ),
"r" ( bzimg.rm_kernel_seg + 0x20 ) );
/* There is no way for the image to return, since we provide
* no return address.
*/
assert ( 0 );
return -ECANCELED; /* -EIMPOSSIBLE */
}
/**
* Load bzImage image into memory
*
* @v image bzImage file
* @ret rc Return status code
*/
int bzimage_load ( struct image *image ) {
struct bzimage_context bzimg;
int rc;
/* Read and parse header from image */
if ( ( rc = bzimage_parse_header ( image, &bzimg,
image->data ) ) != 0 )
return rc;
/* This is a bzImage image, valid or otherwise */
if ( ! image->type )
image->type = &bzimage_image_type;
/* Prepare segments */
if ( ( rc = prep_segment ( bzimg.rm_kernel, bzimg.rm_filesz,
bzimg.rm_memsz ) ) != 0 ) {
DBGC ( image, "bzImage %p could not prepare RM segment: %s\n",
image, strerror ( rc ) );
return rc;
}
if ( ( rc = prep_segment ( bzimg.pm_kernel, bzimg.pm_sz,
bzimg.pm_sz ) ) != 0 ) {
DBGC ( image, "bzImage %p could not prepare PM segment: %s\n",
image, strerror ( rc ) );
return rc;
}
/* Load segments */
memcpy_user ( bzimg.rm_kernel, 0, image->data,
0, bzimg.rm_filesz );
memcpy_user ( bzimg.pm_kernel, 0, image->data,
bzimg.rm_filesz, bzimg.pm_sz );
/* Update and write out header */
bzimage_update_header ( image, &bzimg, bzimg.rm_kernel );
/* Record real-mode segment in image private data field */
image->priv.user = bzimg.rm_kernel;
return 0;
}
/** Linux bzImage image type */
struct image_type bzimage_image_type __image_type ( PROBE_NORMAL ) = {
.name = "bzImage",
.load = bzimage_load,
.exec = bzimage_exec,
};